As one of the photographing techniques of a camera, there is a technique of capturing an image with a shallow depth of field to thereby capture an image in which only a narrow distance range is in focus, objects in front or rear thereof are blurred, and a specific object which is in focus is prominent. The longer a focal distance of a camera is, the shallower a depth of field is, and an image with a shallow depth of field is captured by using a single-lens reflex camera or the like.
On the other hand, a small-sized digital camera or a camera mounted on a smartphone has a small image sensor and a short focal distance, so that it is difficult to capture an image with a shallow depth of field.
Then, an image processing technique has been proposed by which an image with a shallow depth of field is generated on the basis of an image with a deep depth of field and distance information corresponding to the image. In PTL 1, a technique is described by which an image is divided into a plurality of regions, a distance to an object is calculated for each of the divided regions, and blurring processing is performed in accordance with the distance.